


For Science

by akitsuko



Category: Sherlock (TV)
Genre: Coming In Pants, Coming Untouched, Dirty Talk, Established Sherlock Holmes/John Watson, Fantasizing, Finger Sucking, M/M, Plot What Plot/Porn Without Plot, Sherlock Does What He's Told, Smut
Language: English
Status: Completed
Published: 2019-01-22
Updated: 2019-01-22
Packaged: 2019-10-14 06:34:04
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,055
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17503475
Author URL: https://archiveofourown.org/users/akitsuko/pseuds/akitsuko
Summary: It's a quiet and uneventful evening until John puts his fingers in Sherlock's mouth and says filthy things until he comes.





	For Science

**Author's Note:**

  * For [KittieHill](https://archiveofourown.org/users/KittieHill/gifts).



> I combined two requests from KittieHill - John talking dirty until Sherlock comes untouched, and Sherlock sucking on John's fingers. I hope this is the sort of thing you were after!
> 
> Not proof-read.

Sherlock would have been perfectly content to continue the evening as it had begun. John had cooked them a fantastic dinner - some sort of stew - and now they’re resting on the sofa in a comfortable and companionable silence. ‘Death Becomes Her’ plays on the TV, although John is the only one paying the slightest bit of attention as he slouches into the cushions. Sherlock, on the other hand, is idly going over the details of an unsolved murder from several years ago in his mind as he sprawls out across the entire length of the sofa, his hands clasped lightly under his chin and his head pillowed by John's lap. 

 

For once, there's nothing terrible or catastrophic demanding their attention, and while Sherlock adores having a good case to sink his teeth into and stave off his boredom, he’s found that these quiet evenings when he can just enjoy being with John are almost equally satisfying. 

 

Especially when John absent-mindedly runs his fingers through Sherlock’s hair, dragging his nails lightly across his scalp like he’s doing right now, scratching itches that Sherlock hadn't even realised were there. It feels so natural and so good and so right that Sherlock allows his eyes to flutter closed as he basks in the simple show of affection. They're almost never affectionate outside of the flat, and while this doesn't necessarily bother him, it does mean that he makes the most of the experience when it happens. 

 

He arches his head back into the pressure of John's hand, and smiles when he is rewarded with a light tug on his hair before John resumes his previous motions. 

 

This is a good existence, he thinks, as he settles back into his casual examination of the unsolved case. 

 

He rather loses track of time when he is immersed in thought, so it might be seconds or hours that pass before the gentle prod of John's fingers at his mouth bring his consciousness back to the present. His eyes open a touch, and he listens, quickly realising that the film is still playing and therefore deducing that not much time can have passed. John's fingertips, calloused and gentle, smooth across his lips again, and Sherlock looks up at him as he raises a questioning eyebrow. 

 

John just smiles back at him, a smile that to anyone else might appear innocent and sweet. But Sherlock sees how his eyes are crinkled at the corners, and how his gaze lingers on where his fingers sit, and the way his throat moves as he swallows. It’s a smile with an ulterior motive, and a smile that sparks an undeniable tingling sensation in Sherlock’s groin. 

 

He doesn't resist as one of John's fingers slips past his lips and into his mouth, but equally he doesn't respond. He keeps his eyes fixed on John's face, waiting, attempting to anticipate what John is up to, but John turns his attention back to the TV, even as he moves his finger languidly across Sherlock’s tongue. 

 

_ Interesting.  _

 

Sherlock files the unsolved murder away for further perusal at a later date. 

 

It’s an unusual sensation, the way John's finger presses against the inside of his mouth, exploring the fleshiness of his inner cheeks and swiping at his teeth. But it’s not unpleasant. John tastes of clean skin, and his fingernail is short and blunt. And the longer Sherlock observes him, the more it seems that John is as unaffected as he would be if he were swirling that same finger around the rim of a wine glass. 

 

So, experimentally and hoping for some sort of reaction, Sherlock sucks. 

 

But much to his displeasure, John's only response is to push a second finger past his lips too. 

 

He wanted something a bit more substantial. He wanted a sharp and surprised intake of breath. He wanted John's eyelids to become lax, and his gaze to glass over. He wanted to feel a twitch in his muscles, or at least in his cock, which continues to lie soft and uninterested beneath Sherlock’s head. 

 

Even more annoyingly, he can feel his own cock starting to harden, the sexual connotations of having John's fingers in his mouth impossible to ignore. It hardly seems fair that John continues to pay him the bare minimum of attention, and he narrows his eyes at the traitorous response of his own body. 

 

He’s too busy being irritated by his arousal to be prepared for when John stuffs a third finger in to join the first two. Suddenly, Sherlock’s mouth feels very full indeed, and his pyjama bottoms feel several sizes too small. He barely manages to hold back a moan; it feels devastatingly similar to having a certain other part of John's anatomy in his mouth. He can't help but run his tongue over the small protrusions of John's knuckles, glancing up again to assess his expression. 

 

Infuriatingly, John is still apparently immersed in whatever is happening on the screen, and Sherlock is tempted to bite his fingers to get his attention. Except he realises that John's pulse, beating through his fingertips and vibrating against Sherlock’s tongue, is starting to quicken. And, on further concentration, he can feel that John's arousal isn't quite as non-existent as he had assumed it to be moments ago. He might be able to get somewhere with this after all. 

 

Then, still not looking at him, John speaks. “Suck them.”

 

Sherlock’s knee-jerk reaction is to bristle; he doesn't generally enjoy being bossed around, and tends to behave defiantly, flamboyantly, and almost immaturely in the face of instructions. But these are exceptional circumstances. In this flat, with the promise of sexual satisfaction hovering in the air, John could order him to do almost anything and he would be falling over himself trying to please him. Besides, as orders go, this one is no skin off his nose whatsoever. So he obeys. 

 

And never let it be said that he doesn't endeavour to do his best for John. He sucks the fingers further into his mouth, keeping his lips sealed tightly around their bases. He licks them earnestly, exploring every ridge and callous, and soon finds that he’s enjoying himself a great deal more than he had expected. The weight and press of John's fingers are almost a grounding comfort, and he gives them the same attention as he would normally lavish on John's cock. 

 

Just the thought of getting John off with his mouth sends a bolt of arousal through him, and his hips thrust upwards into thin air before he can think to control himself. He’d gladly take John's dick into his mouth alongside his fingers, if John felt inclined to give it to him. 

 

But John is talking again, and apparently that's not what he's after today. “Close your eyes,” he says. “I have a theory I want to test.”

 

Now Sherlock does moan. Adding a scientific angle to the mix… it’s an obvious ploy from John, but it’s also a failsafe. If Sherlock wasn't so focused on the fingers in his mouth, he’d berate himself for having become so predictable. 

 

He closes his eyes, as instructed. The deprivation of sight immediately makes the fullness in his mouth feel that much more divine. 

 

And John's voice reaches him again. “I know you're imagining that you're sucking me off.”

 

Sherlock’s abdominals tighten, and he sucks hard. If he hadn't been imagining it before, he certainly is now. The stretch of his lips around John's girth, the dull ache it causes in his jaw, the weight of him, the salty taste of his precome… 

 

It’s marvellous and perfect, every single time. 

 

“And I want you to imagine it,” John continues. “You’re so damn good at getting me off like that.”

 

His fingers start to move, thrusting shallowly against Sherlock’s lips and tongue. Sherlock is vaguely aware that his own hips are shadowing the rhythm, undulating up against nothing, but it's secondary to the feeling of John caressing his mouth from the inside. 

 

“No one's ever blown me like you do.”

 

Sherlock exhales a shuddering breath through his nose, and he reaches down, fully intending to wank himself off inside his pyjamas. He’s rock hard at this point; he’s not sure what sort of game John is playing, but he does know that it's getting him thoroughly worked up. 

 

But John's voice -  _ Captain _ John's voice - stops him as he goes to lift his waistband, and John's fingers press deeper into his mouth, demanding his attention. “No touching.”

 

His arms flop defeatedly to his sides as his brow creases in frustration. Normally he would complain, but it’s not so easy with his mouth full, and if he’s completely honest, it does pleasantly strange things to his insides and to his cock when John gets all commanding like this. He doesn't even want to disobey him. 

 

Apparently satisfied that Sherlock is listening, John continues again. “Did you practice for me? Maybe you sucked your own fingers, just like this, while you imagined what my dick would feel like instead.”

 

Sherlock’s hips have resumed their rhythmic thrusting, and he can't seem to draw John's fingers as deeply into his mouth as he wants them. 

 

“Or maybe you researched. Watched porn to pick up some techniques. Asked around online. ‘How to give a man the best blowjob of his life’.”

 

Sherlock is whimpering as John separates his fingers a little, and immediately Sherlock runs his tongue along the delicate skin between the bases. His sucking is becoming more haphazard as he drives his hips up with greater urgency. He wishes John would just touch him, or at least let him touch himself. 

 

“But I know it isn't experience that got you those skills. You'd never had a dick in that gorgeous, virgin mouth until mine.”

 

Sherlock fists his hands in the sofa cushions, and his toes curl. 

 

“Knowing I was the first one to take you… it was fucking incredible. And do you know what's even better?”

 

All Sherlock can do is moan. 

 

“Even better is knowing that my dick is the only one that'll ever get past your lips and down your throat again.”

 

How is John able to make the truth sound so utterly filthy? 

 

“I love fucking your mouth. I love coming all over your tongue, so you can taste me. And I love coming on your face, smearing it over your lips. You're so hot after I've made a mess of you.”

 

John’s fingers twist in Sherlock’s mouth. 

 

“But the best part is knowing how badly you just want to  _ take it.” _

 

Sherlock comes, hard and completely untouched. He involuntarily bites down on John's fingers as he rides through several waves of white hot bliss, only letting go when the pleasure begins to subside and his breathing pattern starts returning to normal. 

 

_ What on earth was all that?  _

 

John pulls his fingers out of Sherlock’s mouth, leaving him feeling oddly bereft, and nonchalantly wipes them dry on the sleeve of Sherlock’s dressing gown. Sherlock is far too dazed to find the will to chastise him for it. He peels his eyes open, squinting a little at the seemingly very bright light in the room, and finds that John is looking at him again, this time fondly but with unmistakably smug overtones. 

 

Sherlock clears his throat and tests his voice, which thankfully doesn't sound too broken. “A theory?”

 

“Yeah.” John's fingers are back in his hair. “I wanted to see if I could bring you off without touching you.”

 

For several long moments, Sherlock has no idea how he's supposed to respond to that. He perhaps ought to be a little outraged at John's assumption that such a thing would even be possible; however, the sticky mess in his pyjama bottoms provides undeniable evidence that not only was it indeed possible, but that John had achieved a successful result on his first attempt. 

 

Maybe embarrassment is a more appropriate response. The urge to sulk childishly is suddenly overwhelming. 

 

But then Sherlock shifts, and he realises that John's own erection is now pressed firmly and insistently against the back of his head, and his petulance morphs instantly into calculating deviance as his face splits into a grin. If this is how John wants to play, then Sherlock has a few hypotheses of his own that he wouldn't mind exploring.


End file.
